In many communication and computer systems, information arrives to a multiplexer, switch or information processor at a rate which fluctuates randomly, often with a high degree of correlation in time. The information is buffered for service (the server typically being a communication channel or processing unit) and the service rate may also vary randomly. Accurate capture of the statistical properties of these fluctuations is facilitated by modeling the arrival and service rates as superpositions of a number of independent finite state reversible Markov processes. We call such models separable Markov-modulated rate processes (MMRP).In this work a general mathematical model for separable MMRPs is presented, focusing on Markov-modulated continuous flow models. An efficient procedure for analyzing their performance is derived. It is shown that the ‘state explosion' problem typical of systems composed of a large number of subsystems, can be circumvented because of the separability property, which permits a decomposition of the equations for the equilibrium probabilities of these systems. The decomposition technique (generalizing a method proposed by Kosten) leads to a solution of the equilibrium equations expressed as a sum of terms in Kronecker product form. A key consequence of decomposition is that the computational complexity of the problem is vastly reduced for large systems. Examples are presented to illustrate the power of the solution technique.

Abstract-A fault recovery system that is fast and reliable is essential to today's networks, as it can be used to minimize the impact of the fault on the operation of the network and the services it provides. This paper proposes a methodology for performing automatic protection switching (APS) in optical networks with arbitrary mesh topologies in order to protect the network from fiber link failures. All fiber links interconnecting the optical switches are assumed to be bidirectional. In the scenario considered, the layout of the protection fibers and the setup of the protection switches is implemented in nonreal time, during the setup of the network. When a fiber link fails, the connections that use that link are automatically restored and their signals are routed to their original destination using the protection fibers and protection switches. The protection process proposed is fast, distributed, and autonomous. It restores the network in real time, without relying on a central manager or a centralized database. It is also independent of the topology and the connection state of the network at the time of the failure.

This paper proposes an architecture for a wavelength-interchanging cross-connect (WIXC) that can be used as a switching node of strictly transparent and scalable networks with all-optical routing and all-optical wavelength conversion capabilities. This architecture utilizes all-optical parametric wavelength converters based on difference-frequencygeneration (DFG) or four-wave mixing (FWM), although this work focuses only on the implementation using Difference-Frequency-Generation wavelength converters. The proposed WIXC architecture exploits the unique wavelength mapping properties of parametric wavelength converters: mirror image mapping and simultaneous multichannel wavelength conversion. The derivation of this architecture involves application of a Space/Wavelength transformation to the classical Benes switch fabric. The connection setup for the resulting architecture follows the well established looping algorithm, and the architecture is scalable in both the ports and the wavelengths. The scaling occurs in an orderly fashion, which allows modular upgrades of WIXC's for cost-effective evolution of the networks. The unique properties of the parametric wavelength converter including transparent and multichannel conversion capabilities result in a WIXC architecture that requires fewer wavelength converters while maintaining scalability and transparency. Index Terms-Architecture, optical networks, transparency, wavelength conversion, wavelength division multiplexing (WDM), wavelength interchange cross-connect (WIXC), wavelength selective cross-connect (WSXC). I. INTRODUCTION I N recent years, significant research efforts have been devoted to the design of high-capacity, flexible, cost-effective, reliable, transparent, and scalable multiwavelength optical networks [1], [2]. Dense wavelength division multiplexing (DWDM) point-to-point transmission is emerging as the key technology solution that will help increase capacity and realize national scale networks. The DWDM point-to-point systems

No abstract

Updated and expanded, this second edition of the acclaimed Multiwavelength Optical Networks provides a detailed description of the structure and operation of modern optical networks. It also sets out the analytical tools for network performance evaluation and optimization for current and next generation networks, as well as the latest advances in enabling technologies. Backbone optical networks are evolving to mesh topologies using intelligent network elements; a new optical control plane is taking shape based on GMPLS; and significant advances have occurred in Fiber to the Home/Premises (the 'last mile'), metropolitan area networks, protection and restoration, and IP over WDM. New research on all-optical packet switched networks is also covered in depth. Also included are current trends and new applications on the commercial scene. This book is an invaluable resource for graduate and senior undergraduate students in electrical engineering, computer science, and applied physics, and for practitioners in the telecommunications industry.